This invention relates generally to surgical instruments and particularly to a surgical tissue morcellator for use in minimally invasive, surgical procedures.
Undesirable tissue masses such as fibroid tumors are typically dense, tough, and bulky. These characteristics make it difficult to remove a relatively large and dense tumor using the instruments commonly employed in minimally invasive endoscopic surgery. Endoscopic tissue graspers and cutters have jaws of limited size and inadequate closing force. Therefore, fibroid tumors are commonly removed by open surgery, which permits direct manipulation and cutting. As a result of the open surgical procedure, the patient experiences a long hospital stay and a long healing and recovery period of typically six to eight weeks along with a greater risk of infection and a larger area of scaring.
One minimally invasive surgical procedure involves the use of a surgical cutting instrument for coring tissue affixed thereto. This instrument was developed by the present inventors and is fully described in U.S. Pat. No. 5,488,958. This surgical cutting instrument involves the use of an outer sheath with a distal cutting end that is inserted through a surgical access sheath. The cutting instrument includes an inner member that is inserted through the outer cutting sheath and affixed to the fibroid tissue mass. The outer cutting sheath is then advanced into the tissue mass for coring the affixed tissue. The inner member is again affixed to another portion of the tissue mass, and the coring procedure repeated. This procedure is continued until the fibroid tissue mass is debulked and easily removed through the surgical access sheath. Although well suited for its intended purpose, the surgical cutting instrument is limited in size to the diameter of the surgical access sheath, which is commonly 10 mm in diameter. Furthermore, physicians have requested refinement of the engagement assembly that is positioned at the proximal end of the outer sheath for advancing the outer sheath with respect to the inner member. This refinement was requested to lessen the amount of torque required to core extremely dense fibroid tissue masses. In addition, the engagement assembly also experienced lateral slippage when extremely tough fibroid tissue masses were encountered.
The foregoing problems are solved and a technical advance is achieved in an illustrative surgical tissue morcellator for percutaneously morcellating and debulking tissue during a minimally invasive, endoscopic surgical procedure. The morcellator preferably comprises an outer cutting sheath having a distal cutting end and an insertion member having a distal portion which can be inserted through a passage of the sheath. The distal portion of the insertion member includes a distal end that is atraumatic to tissue and extendable from the distal cutting end of the outer sheath. A connector is disposed on the outer sheath and/or the insertion member and is configured to position the insertion member relative to the outer sheath. During direct insertion into a percutaneous access site, this surgical tissue morcellator advantageously dilates the access site atraumatically and morcellates cores of tissue without being limited to the diameter of introducer sheaths.
The connector includes an adaptor connected to the proximal portion of the outer sheath and is configured to join the proximal sheath portion and the proximal portion of the insertion member. The adaptor includes a bore that communicates with the sheath passage and is configured to receive the proximal portion of the insertion member therein.
To fixedly position the outer sheath and the insertion member relative to each other, the connector advantageously includes a first lock member such as a pin extending into the adaptor bore. The proximal portion of the insertion member includes a second lock member such as a T-shaped slot disposed therein to receive the lock member pin.
To fix the relative position of the tissue mass during the percutaneous morcellating procedure, the insertion member of the morcellator is removed from the outer sheath, and a handle is positioned relative to the outer sheath via the connector. The handle includes a passage extending longitudinally therethrough which communicates with the sheath passage when the handle is positioned relative to the outer sheath. The morcellator further includes a tissue fixation member which is inserted through the sheath and handle passages and has at least a portion that can be extended from the distal cutting end of the sheath. The distal end of the tissue fixation member has a part such as a helical coil or corkscrew that is fixable in tissue.
To advantageously control rotational and longitudinal movement of the outer sheath with respect to the tissue fixation member, the tissue fixation member includes a helical groove in an external surface thereof, and the handle includes a projection that selectively extends into the handle passage and helical groove when the helical groove is positioned in the handle passage. To circumferentially distribute torque applied thereto, the tissue fixation member advantageously includes a plurality of helical grooves such as a five start external thread. Correspondingly, the handle also includes a plurality of projections that selectively extend into the plurality of helical grooves.
To selectively position a projection into a helical groove, the handle includes a rocker arm that extends between an external surface thereof and the handle passage. The projection is positioned about a rocker arm end that is extendable into the handle passage. One or more of these rocker arms are each pivotally mounted in a slot that extends through a wall of the handle. Each projection is mounted on the internal side of the rocker arm at the rocker arm end. Second and third projections are positioned on the external side and at opposite ends of each rocker arm. The handle further advantageously includes a retainer ring that selectively moves longitudinally along the handle to engage the second and third projections on the external side of each rocker arm to position selectively the first projection in a helical groove of the tissue fixation member.
In another configuration, the surgical tissue morcellator comprises the outer cutting sheath with the handle removably connected to the proximal sheath portion. The handle includes one or more slots extending through a wall thereof with a rocker arm pivotally mounted therein. A projection is positioned as previously described on the internal side of each rocker arm. The handle advantageously includes a retainer ring disposed about each rocker arm and movable to engage selectively opposite ends of the rocker arm on the external side thereof. As a result, longitudinal and rotational movement of the outer sheath causes the distal cutting end to rotate and core tissue affixed to a tissue fixation member that is positioned in the handle and sheath passages and engaging the first projection on each rocker arm end.
The morcellator further comprises an adaptor that is disposed on the proximal portion of the outer cutting sheath. The adaptor includes a bore communicating with the handle and sheath passages, the handle being configured for positioning in the bore of the adaptor. The adaptor includes a lock member such as a pin extending into the adaptor bore, and the handle includes another lock member such as a T-shaped slot disposed on the external surface thereof to receive the lock member pin. A tissue fixation member is inserted through the sheath and handle passages and has a distal fixation end which can be extended from the distal cutting end of the outer sheath to affix tissue thereto.